<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>css 浏览器支持</title>

	<style>
		:root {
			--color: red;
		}

		@supports ( (--a: 0)) {
			small {
				display: none
			}
		}

		@supports ( not (--a: 0)) {
			small {
				display: block;
			}
		}

	</style>
</head>
<body>
	<small>你的浏览器不支持 css 变量</small>
	<br>
	<main>Css 方法判断</main>
</body>
</html>